1. Field of the Invention
The invention relates to the field of coupling jacketed metal-clad cables to electrical enclosures while maintaining a continuous ground path between the metal cladding and the enclosure.
2. Description of the Prior Art
A common prior art connector employs a metallic grounding ring having a contact tooth intended to be inserted between the outer surface of the metal cladding and the inner surface of the cable jacket. The ring is split to permit it to accommodate a range of cable diameters and has a fringed end to insure contact between the ground ring and the connector body to provide a good electrical path therebetween. Today's improved cables employ tightly shrunk-on jackets over the cable armor or cladding making insertion of the contact tooth between the cladding and the jacket difficult, if not impossible. Also, such prior art connector must be totally disassembled permitting a loss of connector parts.
Because the contact tooth is difficult to install, it is often improperly installed or discarded entirely by the workman and thus there is no assurance that there is a continuity of ground path between the metal cladding and the electrical enclosure. The fully internal mounting of the ground ring makes it difficult to determine from the outside of the connector whether the ground ring has been improperly installed or discarded.
A second type of connector for jacketed metal clad cables employs a split overlapped ring brought into contact with the metal cladding by means of three set screws operated from outside of the metal body of the connector. The screw holes and the screws themselves offer leakage paths for moisture to enter the connector.
With both types of connectors liquid-tightness and strain relief for the cables is provided by means of a resilient sealing ring have a conically tapered leading surface forced into contact with a complementarily tapered bore within the connector body by the tightening of a gland nut upon the body. The degree of strain relief and liquid-tightness will depend upon how well the tapers match and how tightly the gland nut is applied to the body. Thus, if both types of connectors are tightly applied proper strain relief is applied to the cable and some liquid-tightness. However, the proper ground path can only be established by separate operations which may or may not be carried out properly or at all. In the former case, the contact tooth could be discarded and in the latter the set screws could be left in their loose condition.